From the prior art a noise abatement device is known for an aircraft engine, of the type with moving chevrons: these chevrons can be placed on the trailing edge of the exhaust nozzle of the hot gases of a turbojet, and/or on the trailing edge of the outer cowl of the turbojet.
These chevrons are moving between a passive cruse position, wherein they extend in the extension of the walls onto which they are mounted, and thus practically do not interfere with the involved airflow and an active position used during takeoff or landing, in which these chevrons are inclined with respect to the walls on which they are mounted, causing blending of hot air leaving the exhaust nozzle of gases with the cold air originating from the secondary flow, and/or the blending of this cold air with the external air.
With this blending, it is possible to limit the effect of mutual tearing of the different airflows, and thereby reduce the sound level emitted downstream of the turbojet.
A drawback of these moving chevrons of the prior art is that considerable energy needs to be provided to cause them to move from their passive position to their active position, which requires the use of relatively high actuating means.